title: The diagnostic value of ultrasonography in carpal tunnel syndrome: a comparison between diabetic and non-diabetic patients.
abstract: BACKGROUND
  To compare the value of ultrasonography for diagnosing carpal tunnel syndrome (CTS) in patients with and without diabetes mellitus (DM).
  
  
  METHODS
  Eighty non-DM and 40 DM patients with electromyography-confirmed CTS were assessed and underwent high-resolution ultrasonography of the wrists. Cross-sectional area (CSA) and flattening ratio (FR) of the median nerve were measured at the carpal tunnel outlet (D) and wrist crease (W).
  
  
  RESULTS
  The 80 non-DM and 40 DM patients had 81 and 59 CTS-hands, respectively. The CSA_D and CSA_W were significantly larger in the CTS-hands and DM-CTS-hands compared to the normal control (p < 0.001). However, there is no difference of CSA_D and CSA_W between DM and non-DM CTS patients. Receiver operating characteristics [ROC] curve analysis revealed that CSA_W ≥13 mm² was the most powerful predictor of CTS in DM (area under curve [AUC] = 0.72; sensitivity 72.9%, specificity 61.9%) and non-DM (AUC = 0.72; sensitivity 78.5%, specificity 53.2%) patients. The CSA positively correlated with the distal motor latency of the median compound motor action potential (CMAP), distal sensory latency of the median sensory nerve action potential (SNAP), and latency of the median F wave, but negatively correlated with the amplitude of the median CMAP, amplitude of the median SNAP, and sensory NCV of the median nerve. Stepwise logistic regression revealed that CSA_W (OR 1.21, 95% CI 1.07-1.38; p = 0.003) was independently associated with CTS in DM patients and any 1 mm2 increase in CSA_W increased the rate of CTS by 28%.
  
  
  CONCLUSIONS
  The CSA of the median nerve at the outlet and wrist crease are significantly larger in CTS hands in both DM and non-DM patients compared to normal hands. The CSA of the median nerve by ultrasonography may be a diagnostic tool for evaluating CTS in DM and non-DM patients.
authors.forename: Nai-Wen
authors.initials: NW
authors.lastname: Tsai
authors.forename: Lian-Hui
authors.initials: LH
authors.lastname: Lee
authors.forename: Chi-Ren
authors.initials: CR
authors.lastname: Huang
authors.forename: Wen-Neng
authors.initials: WN
authors.lastname: Chang
authors.forename: Hung-Chen
authors.initials: HC
authors.lastname: Wang
authors.forename: Yu-Jun
authors.initials: YJ
authors.lastname: Lin
authors.forename: Wei-Che
authors.initials: WC
authors.lastname: Lin
authors.forename: Tsu-Kung
authors.initials: TK
authors.lastname: Lin
authors.forename: Ben-Chung
authors.initials: BC
authors.lastname: Cheng
authors.forename: Yu-Jih
authors.initials: YJ
authors.lastname: Su
authors.forename: Chia-Te
authors.initials: CT
authors.lastname: Kung
authors.forename: Shu-Fang
authors.initials: SF
authors.lastname: Chen
authors.forename: Cheng-Hsien
authors.initials: CH
authors.lastname: Lu
mesh_terms: D000368:Aged; D002349:Carpal Tunnel Syndrome / Q000000981:diagnostic imaging* / Q000453:epidemiology; D015897:Comorbidity; D003920:Diabetes Mellitus / Q000453:epidemiology; D005260:Female; D006801:Humans; D008297:Male; D008475:Median Nerve / Q000000981:diagnostic imaging*; D008875:Middle Aged; D011237:Predictive Value of Tests; D014463:Ultrasonography / Q000592:standards*